Periprosthetic shoulder infections are less elusive to diagnostic arthroscopy: commentary on an article by Matthew F. Dilisio, MD, et al.: "arthroscopic tissue culture for the evaluation of periprosthetic shoulder infection".

Abstract

Establishing the diagnosis of deep infection as a complication of shoulder arthroplasty continues to be a challenge1. Preoperative evaluation to identify deep infection after arthroplasty involving a lower extremity (hip or knee replacement) relies mainly on radiographic findings as well as various analyses of peripheral blood (CBC [complete blood-cell count], ESR [erythrocyte sedimentation rate], and CRP [C-reactive protein]) and of synovial fluid (cell count, differential cell count, Gram stain, culture, and various other investigational markers). The sensitivity, specificity, and predictive values of these investigations have turned out to be suboptimal when used after shoulder arthroplasty2,3. This is believed to be due partly to the higher prevalence of infection with low-virulence bacteria, primarily Propionibacterium acnes . To further complicate matters, the clinical importance of intraoperative cultures that are unexpectedly positive for P. acnes is not fully understood4,5. Selected patients presenting with a failed shoulder arthroplasty may be suspected of having a deep infection despite negative preoperative investigations. When the index of suspicion is high, the safest approach may be staged revision surgery, with the goal of the first stage being to remove the failed prosthesis and obtain tissue samples for culture. However, this approach has a substantial …